Anterior throttle carburetor



FIG.4.

INVENTOR. JOSEPH SCHWEISS BY ATTORNEY P 13, 1954 J. SCHWEISS ANTERIORTHROTTLE CARBURETOR Filed Aug. 25, 1950 Patented Apr. 13, 1954 ANTERIORTHROTTLE CARBURETOR Joseph Schweiss, St. Louis, Mo., assignor to CarterCarburetor Corporation, St. Louis, Mo., a

corporation of Delaware Application August 23, 1950, Serial No. 181,065

a Claims.

This invention relates to carburetors for internal combustion enginesand consists particuvantages over standard carburetors of the posteriorthrottle type in that adequate suctions are applied to the nozzle at alltimes for aspirating fuel therefrom and in that the usual acceleratingpump may be omitted. Accordingly, it is the main object of the presentinvention to provide a novel anterior throttle carburetor which issimpler and less expensive than previous carburetors of this type.

Another object is to provide a thermostatic valve in the carburetormixture conduit posterior to the throttle to aid in vaporization of fuelduring cold starting and warm-up.

Another object is to provide a novel fast idle arrangement forcarburetors.

These objects and other more detailed objects hereafter appearing areattained by the structure illustrated in the accompanying drawing inwhich:

Fig. 1 is a side view showing a carburetor and portions of the exhaustand intake manifolds of an internal combustion engine.

Fig. 2 is a vertical, transverse section through my novel carburetorapplied to an engine intake manifold.

Fig. 3 is a detail, vertical section taken on line 3-3 of Fig. 2.

Fig. l is a view of the lower portion of the carburetor structureremoved from the intake manifold and showing a part broken away andsectioned for clearer illustration.

Fig. 5 is a detail section on line 5-'5 of Fig. 2.

Figure 1 shows a portion of an internal combustion engine intakemanifold I with a central portion 3 upon which is mounted the carburetor9. Below the intake manifold is shown a portion of the exhaust manifoldis with a flange H for attachment to the usual tail pipe (not shown). Awarm air stove I2 is attached to the exhaust manifold and connected tothe carburetor by a tube l3.

The carburetor itself is of the downdraft type, including an upper airhorn portion :5, a central mixing chamber portion it, including a seriesof Venturi tubes H, a second series of Venturi tubes l8, and an outletportion H A bowl 20,

adjacent mixing conduit It, encloses the usual,

float 2| and needle valve mechanism (not shown) for maintaining fuel inthe bowl at a substantially constant level. A main metering orifice 22is located in a pocket 23 in the lower, inner portion of the bowl and atthe base of main fuel passage 24. A threaded plug 25 closes pocket 23 atthe bottom. Main fuel nozzle 26 extends upwardly at an angle within themain fuel passage and discharges within smallest Venturi tube I'I.

An anterior throttle valve 23 is mounted in the inlet portion of themixture conduit upon a shaft 29 which mounts a crank 39 on the outsideof the carburetor barrel for attachment to the usual accelerator linkage(not shown). An unbalanced vaporizing valve 3 i with a fixed orifice3|a, is mounted in outlet portion is upon a shaft 32. Carried on theoutside of outlet portion I9 is a cylindrical housing 33 having adetachable cover 35 with a central pintle 35. A spiral, bi-metalthermostat 36 has its center portion secured to pintle 35 and has a hook31 at its outer extremity. A bell crank having arms 38 and 39 is rigidwith the end of shaft 32 within housing 33. Arm 38 has a bent-outextremity receiving thermostat hook 3?. This arrangement is such that atlow temperatures, the thermostat tends to unwind and yieldingly urgevalve 3| toward closed position. As the temperature increases, thethermostat coil winds upon itself so as to reduce the tension on thevaporizing valve and, eventually, hold this valve open.

The other arm 39 of the bell crank is secured to a metal strip 48 whichextends along the inner wall of housing 33.

A port 4| in the wall of thermostat housing 33 provides communicationbetween the same and the interior of the intake manifold i whichreceives and surrounds both the housing and outlet portion I!) of thecarburetor mixture conduit. Curved strip 46 extends over port 4| and hasan opening 42 near its extremity. A fixed port 43 also connects theinterior of the thermostat housing with the intake manifold. Ports 4|and d3 apply intake suction to the inside of the housing for drawingwarm air thereinto through tube l3 and passage 44 from stove 12. In coldstarting, this warm air insures proper heating of the thermostat. Portll being open at such time, due to registry therewith of opening 42therewith, also provides a substantial flow of auxiliary air into themanifold which increases the idling speed of the engine. As thetemperature increases, bell crank arm 39 and valve strip 4|] are rotatedcounterclockwise and port 4| is gradually reduced and ultimately closed.

Outlet portion it, including Venturi tubes H3, is separately formed andhas a flange 45 at its upper portion which is interposed between aflange 4% at the lower end of the carburetor proper and the uppersurface of enlarged portion 8 of the intake manifold. This separateformation of outlet portion |9 permits the interposition of heatresisting gaskets, as at 41, and permits adjustment of the angularity ofthe carburetor and outlet portion, with respect to their vertical axis,as desired and within the limitations of the attaching bolts and boltholes (not shown).

The constant level chamber 20 is connected to the air inlet horn l5 bymeans of a bowl balance vent 5|) and tube 5|.

An angularly disposed cylinder 52 is threadedly received in a boss 53formed on the upper portion of the carburetor mixture conduit oppositemain nozzle 26 and receives a piston 54 constantly urged upwardly bymeans of a coiled spring 55. The piston has a central orifice 55receiving a metering pin which extends downwardly through main nozzle 28and has a reduced tapered portion 58 extending through main meteringorifice element 22. Cylinder 52, beneath piston 54, is connected bymeans of a passage 59 to the carburetor mixture conduit, as at 60. Themetering rod is secured in position by a horse shoe key 63 received inregistering slots in piston 54 and the rod. A plug 52 is snugly receivedin the upper end of the cylinder and a coiled spring of is compressedbetween the enlarged, hexagonal head thereof and the opposed end of theboss 53 to resist unauthorized turning of the cylinder assembly. The end04 of the spring is inserted in registering openings in the cylinder andhead, as shown in Fig. 2, to maintain the assembly. The plug may beremoved simply by snapping spring end 54 out of its receiving holes topermit access to the piston and metering rod assembly for removalthereof.

An inward fiange 65 at the lower end of cylinder 52 provides a stop forthe piston and determines the idling position of the metering rod.Turning of head 62 and the cylinder adjusts this position.

The operation is as follows:

During cold starting, vaporizing valve 31 will be held yieldingly in theclosed position, as in Fig. 2. Suction will be transmitted to the mainnozzle through fixed orifice tie in the vaporizing valve for drawingstarting fuel. Preferably, the throttle valve will be in nearly closedposition at this time. The cranking suction applied to cylinder 52 willbe insufficient to counteract spring 55 so that piston 54 and themetering pin will be in their uppermost positions resulting in maximumeffective opening through the metering orifice for the supply ofstarting fuel. When the engine starts to run, unbalanced valve 3! willbe urged open by the increased, mixture flow therepast and the meteringpin will be drawn downwardly, restricting the effective opening in themetering orifice. During the warm-up, valve 35 will fluctuate with thesuction, providing a restriction at this point for preventing excessivesuction drop in the intake manifold and insuring adequate vaporizationof the fuel. When the suction drops, as during acceleration, the valvewill move counterclockwise (Fig. 2) towards its closed position and themetering pin will lift to provide a richer fuel mixture. The secondseries of Venturi tubes l8 also assist in proper vaporization of thefuel.

As exhaust manifold !0 becomes heated, warm air is drawn past thethermostat which gradually winds upon itself to relax the closingtension applied to the choke valve and, ultimately, hold the choke valveopen. At the same time, this action of the thermostat moves fast idleadjusting strip 40 from its fast idle position, shown in Fig. 4, withport H fully opened, to a normal idle position with port 4! closed andport 43 relied upon to supply merely enough warm air to housing 33 toinsure the holding of the choke valve open. This port may be very smallor even may be omitted, particularly, due to the location of the housingwholly within intake manifold l which of course, reflects the enginetemperature. This feature is of especial value when the engine isstopped after being fully heated. Under this condition, the thermostatwill remain at the engine temperature, even though the flow of warm airfrom the stove is stopped so that the amount of restriction due tovaporizing valve 31 will accurately correspond to the requirements forthe particular temperature of the engine.

The rotatable outlet portion 19 of the carburetor mixture conduitpermits adjustment of the angularity of vaporizing valve 3! to obtainthe best distribution. Also, the outlet arrangement permits mounting ofthe thermostatic control in position to accurately reflect enginetemperature, yet adequate insulation of the outlet parts from thecarburetor proper is provided. The penetration of the metering pinthrough the nozzle will function to impede passage of gas bubblesupwardly therethrough.

During normal idling, whe throttle 28 is nearly closed and piston 54seated on flange 55, metering valve 5? will be in its most restrictingposition, so that only sufiicient fuel is supplied for idling purposes.

The invention may be modified in various respects as will occur to thoseskilled in the art and the exclusive use of all modifications as comewithin the scope of the appended claims is contemplated.

I claim:

1. An internal combustion engine intake system including an intakemanifold with an opening in the central portion of the wall thereof, acarburetor mixing conduit detachably secured to said manifold about saidopening and having an outlet part projecting into said manifold, a flowrestricting valve in said outlet part, and a thermostatic control forsaid valve carried by said part and inside said manifold, said controlbeing removable from said manifold with said conduit for inspection andadjustment.

2. An internal combustion engine intake sys tem as described in claim 1further including a main fuel nozzle discharging into said mixingconduit and a manually operated throttle in said conduit anterior tosaid nozzle. 7

3. An internal combustion engine intake system including an intakemanifold and a carburetor mixing conduit with an outlet part projectinginto said manifold, a flow restricting valve within said outlet part, ahousing on the outside of said outlet part and inside said manifold, athermostatic control for said valve in said housing, and a warm airstove connected to said housing, there being a port in the wall of saidhousing for communicating intake manifold suction to the interior ofsaid housing for drawing warm air past said thermostat.

4. An internal combustion engine intake system as described in claim 3further including a valve element associated with said port and actuableby said thermostat to open said port at low temperatures and therebyincrease the admission of air to and the idling speed of the engine atlow temperatures.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 1,335,665 Deppe Mar. 30, 1920 1,559,756 Kemp Nov. 3, 19251,854,236 Stokes Apr. 19, 1932 2,033,004 Phillips Mar. 3, 1936 2,093,961Ericson Sept. 21, 1937 2,127,444 Emerson Aug. 16, 1938 2,332,440 EricsonOct. 19, 1943 2,563,645 Ericson Aug. 7, 1951

